//服务端
package com.callback;

public class App {
    public void order(Callback callback, String thing){
        //模拟工作
        System.out.println();
        try {
            System.out.println("服务端:" + thing + "下单中......");
            Thread.sleep(5000);  //模型下单处理
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        //回调操作，反馈信息
        System.out.println();
        callback.process("扣款成功");
    }
}
